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Wed, 26 Aug 2026 12:56:28 +0000 (GMT) Received: from shivang.bl1-in.ibm.com (unknown [9.123.12.247]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 26 Aug 2026 12:56:28 +0000 (GMT) From: Shivang Upadhyay To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: sourabhjain@linux.ibm.com, adityag@linux.ibm.com, adri.vero.dev@gmail.com, anushree.mathur@linux.vnet.ibm.com, chleroy@kernel.org, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, shivangu@linux.ibm.com Subject: [PATCH v2] ppc/fadump: collect dump if the collected size is lesser than reserved Date: Wed, 26 Aug 2026 18:26:26 +0530 Message-ID: <20260826125626.2108771-1-shivangu@linux.ibm.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: bKV3ttUB_ujWYOfitf5hcb0B1a8vk348 X-Proofpoint-ORIG-GUID: BBhvg5KCKp4UQaQrX9a1pp8zgIMTFlYJ X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI2MDEwNCBTYWx0ZWRfX54rqtNVKW9LI aeOa1nI0rX2IAw3vfNTNNUkR4xJ+6SKToP5kBz1t91UkvzDOZyeRu2+ZucbgMaawTNAN47lfGce Bbbx+723RcGzslrUVMXjBevXknQIWFJxmp5uhAwvgK2mCctGIvWZmn22iwyojChWLa8SDtRvYTQ jdlSY0fFqI33Oon9vdg0j6a6D3Z2B4O05vB0ebEtcpIW6f+LKA1/ErPQhGy3Rf2b7wuwBP7+jRg XjSCCBFpOds0rEwEOGVAIsk94hfARYvnH4gVr57YS4FLAsMqkinY9UTsLgeYcGXdc2p6tgPzOIR 0FS4gBLK7cpX9olrw8RCW+7CFiAmkgy+oyKBK/juUAQPC6oc0XcUY7pMZQZW7SHxWABlS2gb1XI kqQOEVwVm977Nqs5psBOlSgK5M7gzclEW8qyrfmjBT2Tz2crGHKKhgzn1BIAigrl+LS5b3bMjl9 9n1L5oKqk6gFT+YZPPg== X-Authority-Analysis: v=2.4 cv=QsRuG1yd c=1 sm=1 tr=0 ts=6a8ee285 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=5S_kJhIZ7htqtmZwQG4A:9 X-Proofpoint-Spam-Info: AW1haW4tMjYwODI2MDEwNCBTYWx0ZWRfXxFrycj/w9doj dwCQ+M8UIk5oFyIf5Qj+eHApX1sXrTTh6D/rOPWNwGJwPAzy4UJQL3fr+zR2nXKMBpcCqLhztj7 loAm8d6ukPmfBZ0Kt8odHafz+mADazc= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-26_03,2026-08-26_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 adultscore=0 suspectscore=0 priorityscore=1501 impostorscore=0 spamscore=0 lowpriorityscore=0 clxscore=1011 bulkscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608260104 During Fadump in Qemu VM, when maxcpus value is set to more than current cpus, following failure is observed. [0.000000] rtas: Dump taken by platform is incomplete (-1) This is because the CPU_STATE_DATA is allocated for maxcpus, while the data is only filled for current cpus. As per current implementation of Fadump, dumped_bytes and source_len for a region have to match, Which is failing for qemu's case, Even tough the dumped bytes are reported correctly for only the current cpus. After this /proc/vmcore generatition also fails. Allowing dumped_bytes to be lesser than or equal to allocated length, for CPU_STATE_DATA Fadump region. Reported-by: Anushree Mathur Signed-off-by: Shivang Upadhyay --- ChangeLog: v2: Only allowing lesser size for CPU_STATE_DATE Fadump region. v1: https://lore.kernel.org/qemu-devel/20260429065127.366813-1-shivangu@linux.ibm.com/ --- arch/powerpc/platforms/pseries/rtas-fadump.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/rtas-fadump.c b/arch/powerpc/platforms/pseries/rtas-fadump.c index 3bb4ac2ab6cc..ea1a0a8ac9eb 100644 --- a/arch/powerpc/platforms/pseries/rtas-fadump.c +++ b/arch/powerpc/platforms/pseries/rtas-fadump.c @@ -459,7 +459,10 @@ static int __init rtas_fadump_process(struct fw_dump *fadump_conf) /* Check if the dump data is valid. */ for (int i = 0; i < be16_to_cpu(fdm_active->header.dump_num_sections); i++) { int type = be16_to_cpu(fdm_active->rgn[i].source_data_type); + uint64_t bytes_dumped = be64_to_cpu(fdm_active->rgn[i].bytes_dumped); + uint64_t source_len = be64_to_cpu(fdm_active->rgn[i].source_len); int rc = 0; + int region_collected; switch (type) { case RTAS_FADUMP_CPU_STATE_DATA: @@ -469,8 +472,18 @@ static int __init rtas_fadump_process(struct fw_dump *fadump_conf) pr_err("Dump taken by platform is not valid (%d)\n", i); rc = -EINVAL; } - if (fdm_active->rgn[i].bytes_dumped != fdm_active->rgn[i].source_len) { + /* + * Make sure that dump is collected for entire region. + * CPU_STATE_DATA region is allowed to dump less than allocated space. + */ + region_collected = (bytes_dumped == source_len || + (type == RTAS_FADUMP_CPU_STATE_DATA && bytes_dumped <= source_len)); + + + if (! region_collected) { pr_err("Dump taken by platform is incomplete (%d)\n", i); + pr_debug("type -> %d, bytes_dumped -> %llx, source_len -> %llx\n", + type, bytes_dumped, source_len); rc = -EINVAL; } if (rc) { @@ -482,7 +495,7 @@ static int __init rtas_fadump_process(struct fw_dump *fadump_conf) } break; case RTAS_FADUMP_PARAM_AREA: - if (fdm_active->rgn[i].bytes_dumped != fdm_active->rgn[i].source_len || + if (bytes_dumped != source_len || fdm_active->rgn[i].error_flags != 0) { pr_warn("Failed to process additional parameters! Proceeding anyway..\n"); fadump_conf->param_area = 0; -- 2.54.0